The Food and Drug Administration regulations, which will take effect in May, set standards for an industry that has gone unregulated during a period of explosive growth.

Human tissues can carry diseases, so the way cells are handled can make the difference between a successful treatment and one that doesn't work or, worse, delivers a dangerous infection to the patient.

Brian Lykins, 23, of Minnesota, died in 2001 after receiving infected bone during knee reconstruction surgery, and his parents joined in the lobbying for these new rules.

"Most tissue transplants are safe and successful, but serious adverse events have occurred," said Dr. Jesse Goodman, director of the FDA's Center for Biologics Evaluation and Research. He has been scolded by a Senate committee on several occasions for the delay in issuing rules first proposed in 1997.

The new regulations require tissue processors to take specific steps to prevent the introduction or spread of disease when they recover, process, label, package and distribute human cells, tissues and similar products for transplant.

They also require processors to report certain adverse reactions, to have accurate and complete labeling and to allow FDA inspections.

So far in 2004, there have been about 1 million tissue transplants, up from just 350,000 in 1990. The parts are used for all sorts of treatments: Donated skin can heal burn victims, ligaments can repair knees, bone can be used in hip replacement surgeries. Stem cells from umbilical cord blood can be used to restore the bone marrow of cancer and leukemia patients. Donated sperm and eggs are used for fertility treatments.

While organ donation is run by nonprofit organizations that connect donors directly to surgeons, donated tissue is typically recovered by one agency and handled by a separate processing company — often a for-profit company that turns the material into usable body parts.

While some states regulate tissue banks, there have been few federal rules. The regulations published Thursday are the last of three sets defining federal standards for the industry.

In January, the agency required all tissue banks to register with the FDA to allow for regular inspections.

In May, the FDA said tissue donors, like blood donors, must be screened for infectious diseases. It also required tissue banks to test donors and donated tissue for diseases including HIV, hepatitis B and C, syphilis and Creutzfeldt-Jakob disease, the human form of mad cow disease.

The need for regulations has been covered in depth at two hearings of the Senate Government Affairs Committee. At these sessions, investigators reported widespread problems in the industry: operators who ran multiple tests on recovered tissue in hopes that a second test would find material healthy when the first did not; operators who mishandled cadavers after removing bone and skin; and tissue banks that pooled material from several donors despite the medical risk of one person's tissue contaminating another's.